A member of the Free Syrian Army stands guard as anti-Syrian regime protesters hold a demonstration in Idlib, Syria, Monday. After diplomatic efforts at the UN failed Saturday, the west reluctantly weighs military aid for the rebel Free Syrian Army in the hope that a campaign of attrition will wear down the regular Syrian forces and eventually undermine the Assad regime.

Syria's regime today kept up its assault on the key opposition stronghold of Homs, where local groups say hundreds have been killed since shelling began Feb. 3. With Syria's violence escalating and diplomatic efforts deadlocked at the United Nations, international attention is turning toward a possible military solution to hasten the downfall of President Bashar al-Assad.

A direct Western-led military intervention is being discounted for now. But diplomats and analysts say Western and Arab officials are mulling an option of military support for the rebel Free Syrian Army in the hope that a campaign of attrition will wear down the regular Syrian forces and eventually undermine the Assad regime.

The notion is already winning public support in Washington. Sen. Joe Lieberman (I) of Connecticut has said the FSA deserves a “range of support” including weapons. And Republican presidential candidate Newt Gingrich also has recommended “supplying weapons” and providing the necessary backing to the Syrian opposition to help them topple the Assad regime. It is rumored, but not proven, that Qatar – the tiny Gulf state that armed Libyan rebels last year – may already be supplying funds and weapons to the FSA.

Still, any Western or Arab military support for the ill-equipped FSA almost guarantees a prolonging and intensification of a conflict that already has killed more than 5,400 people and brought the country to the brink of a sectarian civil war.

“I understand the moral outrage that has led some to demand military intervention," says Andrew Exum, a military analyst at the Center for a New American Security in Washington and author of the Abu Muqawama counterinsurgency blog. "But few simple military solutions present themselves.”

Why intervention in Syria is dicier than in Libya

Interest in a military option has grown since Saturday, when Russia and China vetoed a United Nations Security Council resolution condemning the violence in Syria. The deadlock at the UN appears to have exhausted diplomatic options for now. Washington announced yesterday that it had closed the US Embassy in Damascus and recalled all American staff. Several European countries have also recalled their ambassadors to Syria for consultations. And on Tuesday, the six Gulf Arab states said that they were withdrawing their own representatives from Damascus and expelling Syrian ambassadors in their capitals.

Sergei Lavrov, the Russian foreign minister, met with Mr. Assad in Damascus Feb. 7, and said afterwards that the Syrian president was “fully committed” to ending the bloodshed and was ready for dialogue with the opposition. But such assurances are unlikely to persuade the Syrian opposition and the West, particularly given the Syrian Army’s ongoing offensive against the city of Homs which reportedly has killed more than 300 people since Friday.

Still, there is little international appetite to replicate last year's NATO mission in Libya, which helped topple Libyan leader Muammar Gadhafi. Secretary of State Hilary Rodham Clinton said on Sunday that a direct military intervention had been “absolutely ruled out.”

A Western intervention in Syria – even if limited to setting up no-fly zones or havens – poses far greater challenges than in Libya.

Syria’s population density is almost 30 times greater than that of Libya, mainly packed into a handful of cities, which increases the risk of civilian casualties. The Syrian Army is five times larger than the former Libyan army under the late Muammar Qaddafi and much better equipped. Although most of Syria’s anti-aircraft missile systems are aging or obsolete, its air defense network is sufficiently large to pose a challenge to Western aircraft seeking to destroy them prior to policing a no-fly zone. The recent transfer to Syria of advanced Russian anti-ship missiles would represent a grave threat to an amphibious taskforce off the Syrian coast.

“The Syrians will almost certainly resist any intrusion into their sovereignty, so to execute either a NFZ [no-fly zone] or safe haven would mean a fairly extensive air war to reduce Syrian air defenses,” Exum says. “We should also note that any such air operations would take place in some of the most militarily and politically sensitive air space on Earth.”

Syria indeed sits at the nexus of several volatile geopolitical fault lines in the Middle East. They include the conflict with Israel, Syria’s staunch alliance with Iran, Turkey's struggle with ethnic Kurds, Iraq, and Lebanon – over which Syria exerts influence and where it backs the powerful militant Shiite Hezbollah.

“Syria is already an arena for proxy competition between Saudi Arabia and its allies and [rival] Iran and its allies,” says Aram Nerguizian, a military analyst with the Center for Strategic and International Studies in Washington and author of a report published in December on the risks of military intervention in Syria. “Anything that would involve direct Western intervention would be deeply destabilizing at the regional level.”

Divisions arise between rebel commanders

Backing the Free Syrian Army is seen by some as a more palatable alternative to direct intervention. The FSA is responsible for a rising number of attacks against the regular Syrian Army in recent weeks, winning popular support on the ground and stealing the spotlight from the fractious exiled political opposition.

The FSA is composed of battalion-sized units of deserters from the regular army and civilian volunteers. The FSA’s guerrilla-style tactics have helped it establish a few territorial pockets, mainly in the northern Idlib province, some districts of Homs and in Zabadani, a town west of Damascus near the border with Lebanon. But it is lightly armed, suffers from a shortage of weapons and ammunition, and lacks a cohesive command and control structure.

Furthermore, a dispute appears to have arisen among senior opposition commanders.

On Feb. 6, Gen. Mustafa Ahmad al-Sheikh, the most senior officer to have deserted the Syrian Army, announced the creation of the Higher Revolutionary Council to oversee rebel military operations. But Col. Riad al-Assad, who heads the FSA from Turkey, refuses to recognize the new council and said in a statement that the “timing of its creation serves the [Assad] regime." Division within the ranks of the armed opposition could weaken their efforts against Assad.

What rebels would need and who could provide it

Leadership disputes aside, turning the FSA into a coherent military force will require “coordinated action by the intelligence services of a coalition of the willing,” says Jeffrey White, a military analyst with the Washington Institute for Near East Policy.

The FSA, he says, would need an assured supply of arms and ammunition, especially anti-tank missiles, secured means of communication, advice on how to coordinate operations across different regions of Syria, intelligence on Syrian Army operations and vulnerable military infrastructure.

“The intelligence services of the US, the UK, France, Turkey, Jordan, and other states in the region have the know-how and capabilities to do these kinds of things,” Mr. White says. “It would be important to have cooperation from one or more of the states bordering Syria, especially Turkey, in order to establish base facilities, training camps, supply routes and infiltration routes.”

On the other side of the equation, the Syrian Army has suffered from defections and desertions as well as low morale, especially among mainly Sunni conscripts in the regular brigades. But the elite units such as the Fourth Brigade and the Republican Guard remain strong and have spearheaded the crackdown against opposition hubs.

“One of the core assumptions about attrition in Syria – namely that it benefits the opposition – is largely incorrect,” says Nerguizian. “The regime has been preparing for decades for just such a scenario and still has a far higher degree of support than is being reported… That being said, the longer the instability lingers and decays, the more likely it will be that Syria will not be able to avoid a deeply divisive civil war.”